1. Field of the Invention
The present invention relates to a steering wheel for a vehicle, and more particularly to a steering wheel that has an air bag apparatus for the purpose of protecting to the face of a person sitting in a seat in a vehicle.
2. Description of the Related Art
In general, an air bag apparatus that is provided in a vehicular steering wheel has an air bag that is folded up and a cover that covers the air bag. In order to protect a person riding in the vehicle when a collision occurs, the bag is inflated by gas so as to cause the cover to rupture open. Related can be found in the Japanese Patent Application Laid-Open Publication H7-32964.
In the above-noted related technology, however, there is a risk that the ruptured cover will interfere with the chin of the vehicle occupant.
Accordingly, it is an object of the present invention to improve on the above-noted drawback in the related art, by providing a steering wheel for a vehicle which prevents interference by the ruptured cover with the chin of the vehicle occupant.
In order to achieve the above-noted object, a steering wheel for a vehicle according to the present invention includes a boss, a rim, a spoke, and an air bag apparatus. The boss supports the steering shaft. The spoke joins the boss to the rim. The air bag apparatus is supported by the boss, and has a bag, which is folded up and stored therein, and a synthetic resin cover, which covers the bag. When the vehicle is subjected to a collision, to support the occupant, gas is used to inflate the bag, so as to rupture the cover open. The cover includes a side wall that surrounds the periphery of the bag and a front wall that covers the side of the inflation direction of the bag. The front wall has two side rupture lines, on the left and right, a dividing rupture line that joins the two side rupture lines, a center rupture line that extends upwards from the approximate center of the dividing rupture line, and two upper hinges. The two upper hinges are disposed between the side rupture lines and the center rupture line. The side rupture lines, the dividing rupture line, the center rupture line, and the upper hinges define two upper lids at two locations. When the cover ruptures open, the side rupture lines, dividing rupture line, and center rupture line rupture, causing each lid to bend and swing about the upper hinge as a moving axis. The dividing rupture line is disposed at a position so that the upper lids do not interfere with the rim.
According to the above-described arrangement, when the bag inflates so as to cause the rupture of the rupture lines of the cover, the lids swing about the upper hinges, so as to permit the bag to deploy outside the cover. When this happens, the upper lids quickly move to a position that is more toward the front of the vehicle than the rim, without interfering with the rim. The result is the elimination of the risk that the upper lids will interfere with the chin of an occupant.
Because the lids in this case do not hinder the movement of the bag, when the bag flexes in response to the force of movement of the occupant, movement of the bag itself is permitted, this movement acting to softly cushion the occupant. That is, the bag softens the shock to which the occupant is subjected.
In the present invention, the upper hinges can be mutually joined adjacent to the end of the center rupture line, and can also mutually cross at an angle of less than 180xc2x0. It is also possible for each of the upper hinges to cross with the center rupture line at an angle of approximately 90xc2x0.
The upper hinges can form a broken straight line, and can also be mutually separated.
The dividing rupture line can have a center part that is expanded toward the upper hinges, and the center rupture line can have two end parts that extend toward the upper hinges.